In blood tests such as a blood coagulation test, an automatic analyzer that automatically analyzes blood is used. Various solutions are used as reagents in a blood test. A reagent is placed into a designated reagent container and housed inside an automatic analyzer. The reagent is then collected with a thin pipe-shaped collection tube called a probe and dispensed into a reaction container containing a blood sample, and analysis is performed.
By way of an explanation in further detail, as shown in FIG. 4, for example, a plurality of reagent containers 2 are held on a turntable 4 inside an automatic analyzer. As shown in FIG. 5, at the top part of the reagent container 2, a reagent collection opening 221 into which a probe 5 can be inserted is open. The diameter of the reagent collection opening 221 is small, which prevents deterioration of the reagent as a result of oxidation and the like caused by contact with air.
The probe 5 is mounted on the tip of an arm 51. The turntable 4 rotates so as to position a desired reagent container 2 directly underneath the probe 5. Then, through vertical and rotational motions of the arm 51, the probe 5 is made to move between the reagent container 2 and a reaction container (not shown in the figure). A liquid-level sensor is mounted on the tip of the probe 5 and is set up so that even if the height of the liquid surface of the reagent to be collected changes, the tip of the probe 5 can be inserted beneath the liquid surface.
In order to increase the examination processing speed, the turntable 4 rotates not only in one direction but in both left and right directions, quickly and in small movements. Accordingly, as shown in FIG. 5, if the liquid level of the reagent in the reagent container 2 is high, the reagent may, in some cases, splash up and contact the reagent collection opening 221 to form a thin film 6. In such a case, the liquid-level sensor at the tip of the probe 5 will mistakenly detect the film as the liquid surface, and the collection operation will be performed in midair where the reagent does not exist. As a result, even if the probe 5 moves to the reaction container, the reagent will not be dispensed and an incorrect examination value will be obtained.
In order to prevent this sort of mistake from occurring, it will be necessary to make the amount of reagent provided, for example, not exceed one-half the volume of the reagent container so that the reagent does not splash up. But, if the amount of reagent provided is small, the frequency with which to replenish the reagent will necessarily increase. However, since many varieties of reagents are used in blood tests, it is preferable to keep the frequency of replenishment low in order to prevent human-made errors such as mistaking a reagent to be replenished.
Also, when the amount of reagent provided is reduced, an increase in the area of contact with air per unit volume of reagent leads to the drawback of facilitating reagent deterioration. Therefore, it is preferable to have a large amount of reagent provided in the reagent container 2, but for that purpose a means to prevent the reagent from splashing up to the reagent collection opening 221 will be necessary.
Japanese Unexamined Patent Application Publication No. 2000-214171 (JP '171) proposes, in FIG. 1 on page 9, a solution stabilization member that floats on the liquid surface within a reagent container so as to prevent oxidation and the like caused by contact with air and ensure obtaining a stable quality of the reagent.